On your computer with Android Studio 2.2 open the sample project. It wont build until you add a new folder
called raw in the res folder. cp the credentials.json over to the raw folder and then rebuild the project and the
build is hopefully then successful.

In some ways Android Things is far simpler (if you've invested the time and effort to learning Android). Although you can install multiple packages it's best to work on one package at a time else (say) one project will have the pins as outputs and another as inputs and it will end in tears.